//
//  UIImage+Render.m
//  Project
//
//  Created by  CarlsonLee on 2018/12/7.
//  Copyright © 2018年 YANJING. All rights reserved.
//

#import "UIImage+Render.h"
#import <ImageIO/ImageIO.h>
#import <Accelerate/Accelerate.h>
#import <CoreText/CoreText.h>
#import <objc/runtime.h>

@implementation UIImage (Render)

+ (UIImage *)imageRenderingModeImageNamed:(NSString *)imageName
{
    UIImage *image = [UIImage imageNamed:imageName];
    
    return [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
}

+ (UIImage *)gel_imageWithColor:(UIColor *)color {
    return [self gel_imageWithColor:color size:CGSizeMake(1, 1)];
}

+ (UIImage *)gel_imageWithColor:(UIColor *)color size:(CGSize)size {
    if (!color || size.width <= 0 || size.height <= 0) return nil;
    CGRect rect = CGRectMake(0.0f, 0.0f, size.width, size.height);
    UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, color.CGColor);
    CGContextFillRect(context, rect);
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

- (UIColor *)gel_colorAtPoint:(CGPoint)point {
    if (point.x < 0 || point.y < 0) return nil;
    
    CGImageRef imageRef = self.CGImage;
    if (!imageRef) return nil;
    NSUInteger width = CGImageGetWidth(imageRef);
    NSUInteger height = CGImageGetHeight(imageRef);
    if (point.x * self.scale >= width || point.y * self.scale >= height) return nil;
    
    unsigned char *rawData = malloc(height * width * 4);
    if (!rawData) return nil;
    
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    NSUInteger bytesPerPixel = 4;
    NSUInteger bytesPerRow = bytesPerPixel * width;
    NSUInteger bitsPerComponent = 8;
    CGContextRef context = CGBitmapContextCreate(rawData,
                                                 width,
                                                 height,
                                                 bitsPerComponent,
                                                 bytesPerRow,
                                                 colorSpace,
                                                 kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
    CGColorSpaceRelease(colorSpace);
    if (!context) {
        free(rawData);
        return nil;
    }
    CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
    CGContextRelease(context);
    
    long byteIndex = (long)(point.y * self.scale * bytesPerRow) + (long)(point.x * self.scale * bytesPerPixel);
    CGFloat red   = (rawData[byteIndex]     * 1.0) / 255.0;
    CGFloat green = (rawData[byteIndex + 1] * 1.0) / 255.0;
    CGFloat blue  = (rawData[byteIndex + 2] * 1.0) / 255.0;
    CGFloat alpha = (rawData[byteIndex + 3] * 1.0) / 255.0;
    UIColor *color = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
    free(rawData);
    return color;
}

- (BOOL)gel_hasAlphaChannel {
    if (self.CGImage == NULL) return NO;
    CGImageAlphaInfo alpha = CGImageGetAlphaInfo(self.CGImage);
    return (alpha == kCGImageAlphaFirst ||
            alpha == kCGImageAlphaLast ||
            alpha == kCGImageAlphaPremultipliedFirst ||
            alpha == kCGImageAlphaPremultipliedLast);
}

- (UIImage *)gel_imageByCropToRect:(CGRect)rect {
    rect.origin.x *= self.scale;
    rect.origin.y *= self.scale;
    rect.size.width *= self.scale;
    rect.size.height *= self.scale;
    if (rect.size.width <= 0 || rect.size.height <= 0) return nil;
    CGImageRef imageRef = CGImageCreateWithImageInRect(self.CGImage, rect);
    UIImage *image = [UIImage imageWithCGImage:imageRef scale:self.scale orientation:self.imageOrientation];
    CGImageRelease(imageRef);
    return image;
}

- (UIImage *)gel_imageByRoundCornerRadius:(CGFloat)radius {
    return [self gel_imageByRoundCornerRadius:radius corners:UIRectCornerAllCorners borderWidth:0];
}

- (UIImage *)gel_imageByRoundCornerRadius:(CGFloat)radius corners:(UIRectCorner)corners borderWidth:(CGFloat)borderWidth {
    UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
    CGContextScaleCTM(context, 1, -1);
    CGContextTranslateCTM(context, 0, -rect.size.height);
    
    CGFloat minSize = MIN(self.size.width, self.size.height);
    if (borderWidth < minSize / 2) {
        [[UIBezierPath bezierPathWithRoundedRect:CGRectInset(rect, borderWidth, borderWidth) byRoundingCorners:corners cornerRadii:CGSizeMake(radius, borderWidth)] addClip];
        CGContextDrawImage(context, rect, self.CGImage);
    }
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

- (UIImage *)gel_imageByTintColor:(UIColor *)color {
    UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
    CGContextScaleCTM(context, 1, -1);
    CGContextTranslateCTM(context, 0, -rect.size.height);
    CGContextClipToMask(context, rect, self.CGImage);
    [color set];
    CGContextFillRect(context, rect);
    CGContextSetBlendMode(context, kCGBlendModeDestinationIn);
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

- (UIImage *)gel_imageByGrayscale {
    return [self gel_imageByBlurRadius:0 tintColor:nil tintMode:0 saturation:0 maskImage:nil];
}

- (UIImage *)gel_imageByBlurSoft {
    return [self gel_imageByBlurRadius:60 tintColor:[UIColor colorWithWhite:0.84 alpha:0.36] tintMode:kCGBlendModeNormal saturation:1.8 maskImage:nil];
}

- (UIImage *)gel_imageByBlurLight {
    return [self gel_imageByBlurRadius:60 tintColor:[UIColor colorWithWhite:1.0 alpha:0.3] tintMode:kCGBlendModeNormal saturation:1.8 maskImage:nil];
}

- (UIImage *)gel_imageByBlurExtraLight {
    return [self gel_imageByBlurRadius:40 tintColor:[UIColor colorWithWhite:0.97 alpha:0.82] tintMode:kCGBlendModeNormal saturation:1.8 maskImage:nil];
}

- (UIImage *)gel_imageByBlurDark {
    return [self gel_imageByBlurRadius:40 tintColor:[UIColor colorWithWhite:0.11 alpha:0.73] tintMode:kCGBlendModeNormal saturation:1.8 maskImage:nil];
}

- (UIImage *)gel_imageByBlurWithTint:(UIColor *)tintColor {
    const CGFloat EffectColorAlpha = 0.6;
    UIColor *effectColor = tintColor;
    size_t componentCount = CGColorGetNumberOfComponents(tintColor.CGColor);
    if (componentCount == 2) {
        CGFloat b;
        if ([tintColor getWhite:&b alpha:NULL]) {
            effectColor = [UIColor colorWithWhite:b alpha:EffectColorAlpha];
        }
    } else {
        CGFloat r, g, b;
        if ([tintColor getRed:&r green:&g blue:&b alpha:NULL]) {
            effectColor = [UIColor colorWithRed:r green:g blue:b alpha:EffectColorAlpha];
        }
    }
    return [self gel_imageByBlurRadius:20 tintColor:effectColor tintMode:kCGBlendModeNormal saturation:-1.0 maskImage:nil];
}

- (UIImage *)gel_imageByBlurRadius:(CGFloat)blurRadius
                        tintColor:(UIColor *)tintColor
                         tintMode:(CGBlendMode)tintBlendMode
                       saturation:(CGFloat)saturation
                        maskImage:(UIImage *)maskImage {
    if (self.size.width < 1 || self.size.height < 1) {
        NSLog(@"UIImage+LFAdd error: invalid size: (%.2f x %.2f). Both dimensions must be >= 1: %@", self.size.width, self.size.height, self);
        return nil;
    }
    if (!self.CGImage) {
        NSLog(@"UIImage+LFAdd error: inputImage must be backed by a CGImage: %@", self);
        return nil;
    }
    if (maskImage && !maskImage.CGImage) {
        NSLog(@"UIImage+LFAdd error: effectMaskImage must be backed by a CGImage: %@", maskImage);
        return nil;
    }
    
    // iOS7 and above can use new func.
    BOOL hasNewFunc = YES;
    BOOL hasBlur = blurRadius > __FLT_EPSILON__;
    BOOL hasSaturation = fabs(saturation - 1.0) > __FLT_EPSILON__;
    
    CGSize size = self.size;
    CGRect rect = { CGPointZero, size };
    CGFloat scale = self.scale;
    CGImageRef imageRef = self.CGImage;
    BOOL opaque = NO;
    
    if (!hasBlur && !hasSaturation) {
        return [self _gel_mergeImageRef:imageRef tintColor:tintColor tintBlendMode:tintBlendMode maskImage:maskImage opaque:opaque];
    }
    
    vImage_Buffer effect = { 0 }, scratch = { 0 };
    vImage_Buffer *input = NULL, *output = NULL;
    
    vImage_CGImageFormat format = {
        .bitsPerComponent = 8,
        .bitsPerPixel = 32,
        .colorSpace = NULL,
        .bitmapInfo = kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Little, //requests a BGRA buffer.
        .version = 0,
        .decode = NULL,
        .renderingIntent = kCGRenderingIntentDefault
    };
    
    if (hasNewFunc) {
        vImage_Error err;
        err = vImageBuffer_InitWithCGImage(&effect, &format, NULL, imageRef, kvImagePrintDiagnosticsToConsole);
        if (err != kvImageNoError) {
            NSLog(@"UIImage+LFAdd error: vImageBuffer_InitWithCGImage returned error code %zi for inputImage: %@", err, self);
            return nil;
        }
        err = vImageBuffer_Init(&scratch, effect.height, effect.width, format.bitsPerPixel, kvImageNoFlags);
        if (err != kvImageNoError) {
            NSLog(@"UIImage+LFAdd error: vImageBuffer_Init returned error code %zi for inputImage: %@", err, self);
            return nil;
        }
    } else {
        UIGraphicsBeginImageContextWithOptions(size, opaque, scale);
        CGContextRef effectCtx = UIGraphicsGetCurrentContext();
        CGContextScaleCTM(effectCtx, 1.0, -1.0);
        CGContextTranslateCTM(effectCtx, 0, -size.height);
        CGContextDrawImage(effectCtx, rect, imageRef);
        effect.data     = CGBitmapContextGetData(effectCtx);
        effect.width    = CGBitmapContextGetWidth(effectCtx);
        effect.height   = CGBitmapContextGetHeight(effectCtx);
        effect.rowBytes = CGBitmapContextGetBytesPerRow(effectCtx);
        
        UIGraphicsBeginImageContextWithOptions(size, opaque, scale);
        CGContextRef scratchCtx = UIGraphicsGetCurrentContext();
        scratch.data     = CGBitmapContextGetData(scratchCtx);
        scratch.width    = CGBitmapContextGetWidth(scratchCtx);
        scratch.height   = CGBitmapContextGetHeight(scratchCtx);
        scratch.rowBytes = CGBitmapContextGetBytesPerRow(scratchCtx);
    }
    
    input = &effect;
    output = &scratch;
    
    if (hasBlur) {
        // A description of how to compute the box kernel width from the Gaussian
        // radius (aka standard deviation) appears in the SVG spec:
        // http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement
        //
        // For larger values of 's' (s >= 2.0), an approximation can be used: Three
        // successive box-blurs build a piece-wise quadratic convolution kernel, which
        // approximates the Gaussian kernel to within roughly 3%.
        //
        // let d = floor(s * 3*sqrt(2*pi)/4 + 0.5)
        //
        // ... if d is odd, use three box-blurs of size 'd', centered on the output pixel.
        //
        CGFloat inputRadius = blurRadius * scale;
        if (inputRadius - 2.0 < __FLT_EPSILON__) inputRadius = 2.0;
        uint32_t radius = floor((inputRadius * 3.0 * sqrt(2 * M_PI) / 4 + 0.5) / 2);
        radius |= 1; // force radius to be odd so that the three box-blur methodology works.
        int iterations;
        if (blurRadius * scale < 0.5) iterations = 1;
        else if (blurRadius * scale < 1.5) iterations = 2;
        else iterations = 3;
        NSInteger tempSize = vImageBoxConvolve_ARGB8888(input, output, NULL, 0, 0, radius, radius, NULL, kvImageGetTempBufferSize | kvImageEdgeExtend);
        void *temp = malloc(tempSize);
        for (int i = 0; i < iterations; i++) {
            vImageBoxConvolve_ARGB8888(input, output, temp, 0, 0, radius, radius, NULL, kvImageEdgeExtend);
            GEL_SWAP(input, output);
        }
        free(temp);
    }
    
    
    if (hasSaturation) {
        // These values appear in the W3C Filter Effects spec:
        // https://dvcs.w3.org/hg/FXTF/raw-file/default/filters/Publish.html#grayscaleEquivalent
        CGFloat s = saturation;
        CGFloat matrixFloat[] = {
            0.0722 + 0.9278 * s,  0.0722 - 0.0722 * s,  0.0722 - 0.0722 * s,  0,
            0.7152 - 0.7152 * s,  0.7152 + 0.2848 * s,  0.7152 - 0.7152 * s,  0,
            0.2126 - 0.2126 * s,  0.2126 - 0.2126 * s,  0.2126 + 0.7873 * s,  0,
            0,                    0,                    0,                    1,
        };
        const int32_t divisor = 256;
        NSUInteger matrixSize = sizeof(matrixFloat) / sizeof(matrixFloat[0]);
        int16_t matrix[matrixSize];
        for (NSUInteger i = 0; i < matrixSize; ++i) {
            matrix[i] = (int16_t)roundf(matrixFloat[i] * divisor);
        }
        vImageMatrixMultiply_ARGB8888(input, output, matrix, divisor, NULL, NULL, kvImageNoFlags);
        GEL_SWAP(input, output);
    }
    
    UIImage *outputImage = nil;
    if (hasNewFunc) {
        CGImageRef effectCGImage = NULL;
        effectCGImage = vImageCreateCGImageFromBuffer(input, &format, &_gel_cleanupBuffer, NULL, kvImageNoAllocate, NULL);
        if (effectCGImage == NULL) {
            effectCGImage = vImageCreateCGImageFromBuffer(input, &format, NULL, NULL, kvImageNoFlags, NULL);
            free(input->data);
        }
        free(output->data);
        outputImage = [self _gel_mergeImageRef:effectCGImage tintColor:tintColor tintBlendMode:tintBlendMode maskImage:maskImage opaque:opaque];
        CGImageRelease(effectCGImage);
    } else {
        CGImageRef effectCGImage;
        UIImage *effectImage;
        if (input != &effect) effectImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        if (input == &effect) effectImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        effectCGImage = effectImage.CGImage;
        outputImage = [self _gel_mergeImageRef:effectCGImage tintColor:tintColor tintBlendMode:tintBlendMode maskImage:maskImage opaque:opaque];
    }
    return outputImage;
}

// Helper function to handle deferred cleanup of a buffer.
static void _gel_cleanupBuffer(void *userData, void *buf_data) {
    free(buf_data);
}

// Helper function to add tint and mask.
- (UIImage *)_gel_mergeImageRef:(CGImageRef)effectCGImage
                     tintColor:(UIColor *)tintColor
                 tintBlendMode:(CGBlendMode)tintBlendMode
                     maskImage:(UIImage *)maskImage
                        opaque:(BOOL)opaque {
    BOOL hasTint = tintColor != nil && CGColorGetAlpha(tintColor.CGColor) > __FLT_EPSILON__;
    BOOL hasMask = maskImage != nil;
    CGSize size = self.size;
    CGRect rect = { CGPointZero, size };
    CGFloat scale = self.scale;
    
    if (!hasTint && !hasMask) {
        return [UIImage imageWithCGImage:effectCGImage];
    }
    
    UIGraphicsBeginImageContextWithOptions(size, opaque, scale);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextScaleCTM(context, 1.0, -1.0);
    CGContextTranslateCTM(context, 0, -size.height);
    if (hasMask) {
        CGContextDrawImage(context, rect, self.CGImage);
        CGContextSaveGState(context);
        CGContextClipToMask(context, rect, maskImage.CGImage);
    }
    CGContextDrawImage(context, rect, effectCGImage);
    if (hasTint) {
        CGContextSaveGState(context);
        CGContextSetBlendMode(context, tintBlendMode);
        CGContextSetFillColorWithColor(context, tintColor.CGColor);
        CGContextFillRect(context, rect);
        CGContextRestoreGState(context);
    }
    if (hasMask) {
        CGContextRestoreGState(context);
    }
    UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return outputImage;
}


- (UIImage *)gel_blurredImageWithRadius:(CGFloat)radius {
    return [self gel_blurredImageWithRadius:radius
                                iterations:3
                                 tintColor:nil
                          tintColorPercent:0
                                 blendMode:0];
}


- (UIImage *)gel_blurredImageWithRadius:(CGFloat)radius
                            iterations:(NSUInteger)iterations
                             tintColor:(UIColor *)tintColor
                      tintColorPercent:(CGFloat) tintColorPercent
                             blendMode:(CGBlendMode) blendMode {
    //image must be nonzero size
    if (floorf(self.size.width) * floorf(self.size.height) <= 0.0f) return self;
    
    //boxsize must be an odd integer
    uint32_t boxSize = (uint32_t)(radius * self.scale);
    if (boxSize % 2 == 0) boxSize ++;
    
    //create image buffers
    CGImageRef imageRef = self.CGImage;
    vImage_Buffer buffer1, buffer2;
    buffer1.width = buffer2.width = CGImageGetWidth(imageRef);
    buffer1.height = buffer2.height = CGImageGetHeight(imageRef);
    buffer1.rowBytes = buffer2.rowBytes = CGImageGetBytesPerRow(imageRef);
    size_t bytes = buffer1.rowBytes * buffer1.height;
    buffer1.data = malloc(bytes);
    buffer2.data = malloc(bytes);
    
    //create temp buffer
    void *tempBuffer = malloc((size_t)vImageBoxConvolve_ARGB8888(&buffer1, &buffer2, NULL, 0, 0, boxSize, boxSize,
                                                                 NULL, kvImageEdgeExtend + kvImageGetTempBufferSize));
    
    //copy image data
    CFDataRef dataSource = CGDataProviderCopyData(CGImageGetDataProvider(imageRef));
    memcpy(buffer1.data, CFDataGetBytePtr(dataSource), bytes);
    CFRelease(dataSource);
    
    for (NSUInteger i = 0; i < iterations; i++)
    {
        //perform blur
        vImageBoxConvolve_ARGB8888(&buffer1, &buffer2, tempBuffer, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
        
        //swap buffers
        void *temp = buffer1.data;
        buffer1.data = buffer2.data;
        buffer2.data = temp;
    }
    
    //free buffers
    free(buffer2.data);
    free(tempBuffer);
    
    //create image context from buffer
    CGContextRef ctx = CGBitmapContextCreate(buffer1.data, buffer1.width, buffer1.height,
                                             8, buffer1.rowBytes, CGImageGetColorSpace(imageRef),
                                             CGImageGetBitmapInfo(imageRef));
    
    //apply tint
    if (tintColor && CGColorGetAlpha(tintColor.CGColor) > 0.0f)
    {
        CGContextSetFillColorWithColor(ctx, [tintColor colorWithAlphaComponent:tintColorPercent].CGColor);
        CGContextSetBlendMode(ctx, blendMode); ///kCGBlendModeDarken
        CGContextFillRect(ctx, CGRectMake(0, 0, buffer1.width, buffer1.height));
    }
    
    //create image from context
    imageRef = CGBitmapContextCreateImage(ctx);
    UIImage *image = [UIImage imageWithCGImage:imageRef scale:self.scale orientation:self.imageOrientation];
    CGImageRelease(imageRef);
    CGContextRelease(ctx);
    free(buffer1.data);
    return image;
    
}

@end
